Difference in semantics?

Discussion created by petronilamandeno on Sep 15, 2010
Latest reply on Jun 11, 2013 by MKennedy-esristaff

I have a set of well points (provided by DOGGR) initially stored in an table with lat/longs.  I created points assuming that the coordinate system was GCS_WGS_1984 with a D_WGS_1984 datum.  Another person did the exact same thing several years ago, but they assumed Geographic Coordinate System for the coordinate system, WGS1984 datum.

I have loaded both shapefiles into an MXD with the data frame set to NAD_1983_UTM_Zone_11N and they don't match (they should, exact same points except the newer one has a few more).  They are offset by about 70 meters on the x and 15 meters on the y.

My questions:
What is the difference between this:
Geographic Coordinate System: GCS_WGS_1984
Datum:  D_WGS_1984
Prime Meridian:  Greenwich
Angular Unit:  Degree

And this:
Geographic Coordinate System: Geographic Coordinate System
Datum:  WGS84
Prime Meridian:  Greenwich
Angular Unit:  degree

Any clues?

Thanks in advance.